1. Field of the Invention
The present invention relates to an optical fiber structure that combines multiple optical fibers and is used for optical circuit packages, optical circuit devices and other applications pertaining to optical communication and optical information processing, as well as a method of manufacturing the same.
2. Description of the Related Art
An optical fiber structure is constituted by multiple optical fibers that are aligned and affixed to each other, and has the advantage of providing the smallest configuration for optical fiber core wiring. Traditionally, coated optical fiber ribbons have often been used as such optical fiber structures. For example, coated optical fiber ribbons are used to store multiple optical fibers in an optical fiber cable in a compact and dense manner, and they are also utilized for multi-core wiring of optical fibers between devices or within a single device.
As the conversion of communication lines to optical fibers progresses, even to the last mile, it has become necessary to branch multi-core coated optical fiber ribbons and connect them to individual subscribers. To do this, coated optical fiber ribbons must be split and branched into single optical fibers on site, or otherwise coated optical fiber ribbons having branching sections at desired positions are required. In general, a method of manually splitting coated optical fiber ribbons or achieving the same effect mechanically by means of a simple jig is used to produce branching sections, both during manufacturing and on-site connection. However, the process of splitting coated optical fiber ribbon manually or mechanically using a jig presents several problems, such as the need for a large force to split the optical fibers, generation of an excessive stress received by the optical fibers at the time of splitting, and easy occurrence of unnecessary splitting. To improve these problems, improved structures such as double-cover structures for splittable coated optical fiber ribbons (Japanese Patent Laid-open Nos. Hei 7-134230 and 2002-174759) and a method involving the use of a connection resin offering high peelability between optical fibers (Japanese Patent Laid-open No. 2002-189153) have been proposed, among others. However, practical splittable coated optical fiber ribbons have not been provided so far. Also, the method involving the use of a connection resin offering high peelability presents a new set of problems, such as contamination of surroundings and consequent interference with the connection process due to remnants of the connection resin layer peeling off at the time of splitting.
Also, a method of manufacturing an optical fiber structure by aligning multiple optical fibers in parallel, covering these optical fibers, and then creating an integrated bundle of multiple optical fibers, is also known (Japanese Patent Laid-open No. Hei 6-123826). Under this conventional manufacturing method, however, positioning and application jigs are required that are appropriate for the number of optical fibers in the optical fiber structure as well as the optical fiber pitch. In the case of an optical fiber structure having a specific number of optical fibers and/or specific optical fiber pitch, therefore, a specific manufacturing apparatus prepared exclusively for the applicable conditions must be used to manufacture the optical fiber structure or the existing application jig must be replaced with a specific jig, which prevents efficient manufacture of an optical fiber structure having a desired number of optical fibers.